Motor control.



W. M. OUMMISKEY,

MOTOR CONTROL.

APPLICATION FILED APR. 6, 1911.

ATTORNEYS fio y32, 33 are muren STATES Parenti WILLIAIVI M. CUMMISKEY, OF

HONESDALE, PENNSYLVANIA, ASSIGNOR, BY MESNE ASSIGNMENTS, TO GRNEY ELECTRIC ELEV.iOlt` COMPANY, OF HNESDALE, PENNSYLVANIA, A CORPORATION OF PENNSYLVANIA.

MOTR CONTROL. i

Application lcd April 6, 1911.

To all 'uf/10m 'it may concern.'

Be it known that I, W'iLLrAM M. CUM- nisiinr. a' citizen of the United States, and a resident of lvlonesdale, in Wayne county and State of Pennsylvania, United States of America, have invented certain new and useful Improvements which the following is a specification.

My invention relates to improvements in systems of control for electric motors, and its object is to automatically prevent the connection of a resistance across the armature terminals of the motor unless the armature is rotating at a predetermined rate.

l will describe my invention in the following specification and point out the novel features thereof in the appended claims.

The drawing herewith is a diagram ol' certain lelectrical apparatus and their connecting circuits.

-l` and designate themains trein a suitahle source el electrical supply.

l0 is the shunt field winding` of an ,electric motor which, as shown in the drawing, is directly connected across these mains. l1 is the armatureot' this motor. and 12 and 13 are its leads or terminals.

14 is starting resistance which is ar ranged to he connected in series withA the armature, and 15 is another resistance which is arranged to he connected across the armature or in shunt therewith in slowing down the motor.

At 2O is a manually operated switch which comprises a hand lever on which is a movahle contact 21 in electrical connection with the -lor positive main, and stationary contacts 22, 23, 24, 25, 26 and 27, onto which the movable contact 21 may he moved.

30 is a solenoid which forms .a part of an electromagnetically actuated' reversing switch. 3l is the core of ,this solenoid, and

contact plates which are connectedwith lout insulated from this core.

311 and 35 are stationary contacts, which are connected with the and mains, respectively. To another stationary contact 36 is connected the motor armature lead 13. The stationary contact 37 is connected by a conductor 1G through the resistance 14 with the other armature lead 12. a

One terminal of the solenoid 30 is con nected hy a conductor 28 with the station arv contact 2% of the controlling 'switch 20,

S eccation of Letters Patent.

in Motor Control, of

vcore or plunger Patented 2t?, 1914i.

Serial No. 819,22

lts other terminal is connected with the main.,

et@ is another solenoid, and its core. This core is n'iechanically `reared to rotate a shaft '-12 on which are a plurality of cams which are so placed on the shaft that when the latter is rotated hy the movement of the solenoid core eti they `will, successively move switch arlns or levers 4.3, te, l5 and 46, against stationary contacts in their paths of movement. rlhese switch levers are electricallj,T connected together, and with the conductor 16, and the stationary contacts with whichthey coact'are connected with different parts of the starting resistance 14. @ne terminal of the solenoid 40 is connected by a conductor47 through contacts 58 which are controlled by a contact plate 59, and` with the stationary contacts 26 and 27 of the hand switch 2G. lts other terminal is connected with the main.

50 is a solenoid, and 5l its core. the device helore described, is arranged to rotate a cam shaft 52 and to successively nieve the switch levers 53, 54', 55 and 5G against stationary contacts which are con* nected, in this case, with different parts of the slow-down resistance 15. These switch levets'are connected together and with the armature lead 13. One of the terminals of the solenoid 50 is connected with a stationary contact of a controlling magnet or solenoid S0 hy a conductor 57. A stationary contact 65, similar to 64, is connected by a conductor (3G through contacts 48 which are' controlled hy contact plate 49 with the stationary contacts and 23 of switch 20. The other terminal of solenoid 50 is con` nected with the main.

The controlling magnet or solenoid 60 comprises a winding 61,- tlie .terminals o' which are connected directly across the terminals of the motor armature 11, and a o2 which carries a Contact plate 63. rlhis plate is arranged to he drawn up against the contacts 64 and 65\ under conditions which 1 will specifically point out later.

When the parts are in the positions in which they are shown in the diagram the This, like motor is at rest. New, it an operator moveslot the two stationary contacts 22 and 24. As has been shown, the contact 21 is connected with the main. This movement of. the hand-switch will thcn complete a circuit through the conductor 28 and the soleniod Winding 30 to the negative main. Solenoid 30 will then be energized and Will lift the contact plates 32 and 38 up against the stationary contacts 84, 36, and 37, 35, respectively. This will complete a circuit from the -lmain through contacts 34, 36, conductor 18, te and through the motor armature 11, thence through conductor 12, starting resistance 14, conductor 16, and contacts 37, 35 to the negative main. The motor will then be started. It will be noted that bringing the contact 21 of the hand-switch upon the contact will not then complete a circuit through-the solenoid becauseithe low resistance of the motor armature will practically short-circuit the high resistance Winding 61 of the 'magnet 60 sltA -at there Will be no connection between its .stationary contacts 63, 64. That is, the pah fer 'the current from the -lmain throng outacts 21 and 22 extends through conductors G6, contacts 48, 48, which are now bridged by the contact plate 49, to the stationary contact Where it ends. A further movement of the hand switch lever will bring it into the position indicated by the dotted line at' B. The contact 21 still remains on the contact 24, but will `now also cover the stationare nonv bridged by-the plate 59, to and through the solenoid Winding 40, and thence to the main. This solenoid Will then be energiycd and will lilt its core, rotating the shaft 42 and closing the contacts below the switch levers 48, 44, 45 and '46 consecutively, to cut out the starting resistance 14 in a plurality of steps. The rotation of the shaft 42 is preferably retarded by a dash-pot in the usual land Well-,known manner. The movement oli the solenoid core will at the same time lift the contact plate 49 from the contacts 48. Now the armature 11 of the motor will get its current directly from the source ot supply and will consequently run at its full speed. In doing this it Will generate 'a counter-electromotive force of sutlicient strength to energize the winding G1 of the magnet 60, and will cause the contact plate 63 to be brought into contact with and to bridge the contacts 64 and 65. W'hen it is desired to slow-down the inotor, the handle of the manually operated switch is returned .to the position A.. This breaks the circuit through solenoid 40 so that its core will drop and lift the contact levers which it controls to reinsert the resistance 14 in the armature circuit. It will also cause the plato 49 to again bridge contact 48, 48. Now, a circuit will be established from the -lmain through across or in shunt with the motor armature. I

The rotation of the latter in its magnetic field will cause it to generate a current through this resistance 15, thus putting a considerable load upon the motor and causing it to sloa7 down. Further upward movement of the solenoid core 51 Willcause the contact lever 54 to close against its contact, short-circuiting a part of the resistance 15, and thus increasing the load upon the armature. Similarly, the levers 55 and 56 will short-circuit more of the resistance 15 in two more steps, causing the motor to run very slowly. The rotation of the' cam shaft 52 is also preferably retarded by a dash-pot.

It may be seen that if when at any time l the lever ot the manually operated switch 20 is moved back to its A position, the motor armature is rotating too slowly to ymaintain the core G2 in Vmagnet 60 in its raised position, the solenoid 50 which controls the slowdown resistance 15, cannot be energized. Also, if, during the slow-.down operation described, the motor loses enough of its speed to cause the core 62 to drop, the circuit'through solenoid 50 will be broken, and the contact levers which it controls raised to disconnect the slow-down resistance 15. Obviousl y, the electroinotive force .generated by the motor armature, must be considerably greater to cause the core 62 to be raised than it need be'to maintain it in its raised position. t isfalso to be noted that the resistance 15 'cannot be connected across the arm av ture until. the resistance 14 is connected in series with it, because of the arrangement of the contacts 48, 48 and the contact-plate A49 which breaks the circuit ott the solenoid 50 Whenever' the plunger of the solenoid 40 is raised. The solenoid 40 is also made inoperative Whenever the core of the solenoid l 50 is raised because the circuit of thesolenoid 40 is broken whenever the contact plate 59 is raised from the stationary contacts 58, 58. lVhn the lever of hand switch 20 is brought back toits central position the its incassa @i tion to he connected with the -lmain when the Contact plate is raised, and has another conductor '72 leading to the main. Similar operations to those described may take place when the lever of the manually operated switch moved to the right. lut in thisI case a. magnet 31"* of the reversing switch will raise contact plates 32A and 33A against cci-tain stationary contacts which are so connected to theA mains and with the motor armature as to cause the current in the latter to llow in the opposite direction so that its direction of rotation will be reversed.

lVliat l claim is.`

l. Jin electric motor havingr an ariiiaturd' a starting' resistance, a circuit closer for said startingresistance, a slow-down resistance arranged to be connected across the armature, acircuit .closer for said slowdown resistance, and means for rendering said circuit closer for the slow-down resistance automatically dependent upon both the speed of the motor armature and upoii the position of the circuit closer for the starting resistance.

2. An electiic motor having an armature, a resistance, manually controlled means for connecting said resistance across the armature, and means automatically actuated by the rotation of the armature for controlling said manually controlled means.

3. An electric motor having an armature, a'resistance, a circuit closer arranged to connect said resistance across t-he armature,

and an electroresponsive device independent of said circuit closer automatically controlled by the rotation of the armature for controlling the circuit closer. i

4. An electric motor having an armature, a resistance, a circuit closer arranged. to connect said resistance across the armature, an actuating device for the circuit closer, and an electroresponsive device connected across thek armature and arranged to render said actuatingn device inoperative except when the motor is running* above -a predetermined rate of speed.

5. An electric motor having an armature, a resistance, a-circuit closer arranged to,

connect said resistance across 'the armature,

actuating the circuit an electromagnet for closer, a circuit for said magnet, a manually operated switch, and an electromagnetioally actuated switch in the magnet circuit, said actuated switch being arranged to he actuated by the rotation of the motor armature.

6. An electricmotor having' an armature, a resistance, a'circuit closer having aplurality of switch arms for connecting .diiierent amounts of said resistance across the armature` Aan electromagnet for actuating the circuit closer, a circuit for said magnet, a manually operated switch, and an autoture,

matic switch in the aiitoinaticswitch comprising an eleciyroniag net connected across the motor armature.

magnet circuit s d s. in electric' motor having an arm a resistance', a circuit closer connect saidA resistance across the arniaturer a manually `operated switch for controlling the iiiotor,:said switch having a full-speed and an intermediate slow-speed position, said intermediate position beine; arranged to control the resistance circuit clos, and automatic means for ,rendering the resistance vcircuit closer inoperative, except when the motor armature is rotating,r above a predetermined rate of speed.

S. An electric motor haring an armature3 a startingresistance arranged to be connected in series with the armature, a circuit closer for said starting resistance; a slow-down resistance arranged to he' connected across the armature,a circuit closer for said slow-down resistance; a manually operated switch i'or controlling' both of said circuit closers, said switch having Ya full speed position for controlling' the starting resistance circuit closer, and an intermediate slow speed position for controlling the slows down resistance circuit closer; and aiitomatic means for rendering the slow-down resistance circuit closer inoperative .while said manually operated switch is being moved into its full speed position.

9. An electric motor having an armature, a starting resistance arranged to be conaturejl to necte'd-in series with the armature, a circuit to cut out said starting resistance across the armature; a manually operated switch for controlling both of said circuit closers, said switch having a fullspeed position for controlling the starting; resistance circuit closer, and an intermediate slow speed position for controlling-the slow-down resistance circuit closer, and. automatic means for rendering the slowdown resistance closer inoperative when manually operated switch is being moved into its full-speed position.

10. An electric motor haviiiifan armaa starting resistance arranged #to-lie connected in series with the armature, a circuit closer for said starting resistance; a slow-down resistance arranged tolse connected across thearmatiire, a circuit closer for said slowdown resistance; a manually operated switch for controllingr botli of said circuit closers, said' switch having a, fullspeed position for controlling theA starting 'resistance circuit closer, and an intermedi- 'ate slow-speed position for controlling the a circuit closer arranged toV4 connect different amounts of slowdown re-` rea fili

resistance circuit closer inoperative when said manually operated switch is being' moved into its full-speed position and other means for renderingn the slow-down resist- 'ance circuit closer inoperative when the starting resistance circuit closer is closed.

1l. An electric motor having an armature, a starting resistance arranged to be connected inseries with the armature, a circuit closer for said starting resistance; a slowdown resistance arranged to be connected across the armature, a circuit closer for said slow-down resistance; a manuall7 operated switch for controlling both of said circuit close'rs, said switch having a full-speed position for controlling the startimgr resistance circuit closer, and an intermediate slowspeed position for controlling the slow-down resistance circuit closer.l automatic means for rendering the slow-down resistance circuit -closer inoperative w'hen said manually7 operated switch is being moved into its fullspeed position, and other means for rendering the starting 'resistance circuit closer inoperative when the slow-down resistance circuit closer is closed.

l2. An electric motor having an armature, a starting?r resistance arranged to be connected in series with the armature, a circuit closer for said starting' resistance; a slowdown resistance arranged to be connected across the armature, a circuit closer for said slow-down resistance; a manuali)-v operated switch for controlling both oi" said circuit closers, said switch haring a full-speed po- .sition for controllingl the startingr re; circuit closer, and an intermediateslowspeed position for controlling the slow-down resistan Je circuit closer7 automatic means for rendering' the slow-down resistance circuit. eicser inoperative when said manually operated switch is being moved into its fullspeed position, means for rendering.,r the slow-down resistance circuit closer inoperative when the stai-tine; resistance circuit closer is closed, and other means for rendering the startingT resistance circuit closer inoperative when the slow-down resistance circuit closer is closed.

13. A, motor having an armature, a starting resistance arranged to be connected in messes therefor; a slow-down resistance` a circuit closer arranged to connect ditierent amounts of said slow-down resistance across the armature in a plurality of steps., an actuating magnet therefor; circuits` for both of said actuating magnets, a manually operated switch for controllingT the circuits said switch havinga full-speed position for controlling the starting; resistance circuit closer, and an intermediate position for controllingr the slow-down resistance circuit closer; means controlled by the slow-down resistance circuit closer actuating magnet for breakingr the circuit of the starting resistance circuit closer actuatingV magnet when the slow-down resistance circuit closer is closed; means for bre-kiner the circuit of the slow-down resistance circuit closer actuating magnet when the starting resistance circuit closer is closed; and an automatic switch in the slow-down resistance circuit closer actuating magnet circuit arranged to prevent thel closing of said circuit except when the motor armature is rotating above a ini-edetermined rate of speed, said automatic switch comprising` an electromagnet connected across the motor armature.

1-11. An electric motor havingr an armature, a starting;- resistance, a. circuit closer for said starting resistance, a slow-down resistance arranged to be connected across the armature, a circuit closer for the slow-down resistance, electro-responsive means for actuating thc circuit closer for the slow-down resistance, a control switch dependent upon the speed of the motor armature, and means tor rendering' said electro-responsive means automatically dependent upon said control switch and upon the circuit closer for the starting resistance.

In testimony whereof l have signed my name to this speciication in the presence of two subscribing' witnesses.

WLLAM M. CUMMISKEY.

Vitnesses C, R. CALLowAY, LEON H. Ross. 

